Measles, Mumps, Rubella (MMR) Vaccine

Your child will need two doses, at 12 to 15 months and 4 to 6 years of age. Here's why this vaccination is so crucial for your little one's health, plus answers to common concerns.

Measles is a highly contagious illness that is spread through coughing, sneezing and even breathing. It can cause a rash all over the body, fever, runny nose, eye irritation and cough. Measles can result in an ear infection and also progress to pneumonia, infection of the brain (encephalitis), seizures, permanent brain damage and even death. Measles remains a common disease in many parts of the world and is a leading, preventable cause of infant mortality globally. Each year, an estimated 10 million people are affected by measles and measles kills almost 90,000 people around the world.

While the CDC declared the disease eliminated in the U.S. in 2000 (meaning it was not continuously transmitted for at least 12 months), the risk of an outbreak is always present. Travelers can bring measles into the United States where the disease still exists, and they can spread measles to people who are unvaccinated, including those who refuse to be vaccinated or those who can't get the vaccine because they're too young or have specific health conditions.

Mumps is spread through saliva or mucus through the mouth, nose or throat and causes headache, fever, loss of appetite, muscle pain and inflammation of the salivary glands that leads to swelling of the cheeks and jaws. Mumps can cause complications such as meningitis and hearing loss, especially in people who are not vaccinated. Even though the vaccine has drastically reduced mumps cases, outbreaks continue to occur in the United States.

Rubella (also known as German measles) is spread through respiratory secretions from an infected person who coughs or sneezes. It causes a slight fever, rash, swollen tender glands at the back of the neck and, occasionally, arthritis-like symptoms in the joints. Sometimes the symptoms are so mild that they're missed. However the greatest danger from rubella is to unborn babies who, if their mothers contract rubella during early pregnancy, are at risk of being stillborn or born deaf, blind, mentally impaired, or with small brain or heart defects. So immunization in early childhood is recommended — both to reduce the risk of infected children exposing pregnant women, including their own mothers, and to ensure girl babies will also be protected when they reach childbearing age.

There are two MMR vaccines licensed for use in the United States that provide protection against measles, mumps, and rubella. The other vaccine, called MMRV, also protects against chickenpox (varicella). MMRV can be used in children 12 months to 12 years of age.

The dose: Two doses are recommended by the CDC. The first is given at 12 to 15 months, the second between 4 and 6 years of age (though it can be given any time 28 days or more after the first dose). For babies who will be traveling internationally, however, a dose is recommended between 6 and 12 months. Kids who receive their first dose before a year of age should still also receive the two recommended doses per the above schedule.

Understanding the risks: The odds of your child experiencing any side effects to the MMR vaccine are very small. Reactions are usually very mild, and they don't usually occur until a week or two after the shot. Some kids may get a mild fever or rash (which will go away on its own and is not contagious or concerning in any way). Studies have repeatedly and definitively shown there is absolutely no link between the MMR vaccine and autism or other developmental disorders.

For adults: Women who are planning to get pregnant need to be up-to-date on their MMR vaccine. Adults who received two doses of the MMR vaccine as children are considered protected for life and usually don't need a booster dose, though one may be necessary if you're at risk because of a mumps outbreak. If you’re unsure whether you were vaccinated or need a booster dose, talk with your health care provider — there's no harm in getting the MMR vaccine again if you already received it.

From the What to Expect editorial team and Heidi Murkoff, author of What to Expect the First Year. Health information on this site is based on peer-reviewed medical journals and highly respected health organizations and institutions including ACOG (American College of Obstetricians and Gynecologists), CDC (Centers for Disease Control and Prevention) and AAP (American Academy of Pediatrics), as well as the What to Expect books by Heidi Murkoff.

View Sources

Medically reviewed by the Centers for Disease Control and Prevention, May 2018.

What to Expect the First Year, 3rd edition, Heidi Murkoff and Sharon Mazel.